1. Field of the Invention
The present invention relates to a location detection apparatus.
2. Description of Related Art
Patent Document 1 proposes a range sensor as one technique for detecting a distance to and a direction to an object existing in an external space. The range sensor includes a light source, a projection mirror, a light reception mirror, and a light receiving element. The projection mirror and the light reception mirror are rotatable together. The light from the light source is incident on the projection mirror along a rotation axis, and the projection mirror reflects the incident light to the external space. Then, the light may be reflected by an irradiated object (i.e., an object to be detected) existing in the external space, and the light from the object is reflected by the light reception mirror and conducted to the light receiving element. Based on a result of the light reception by the light receiving element, the range sensor detects a distance to and a direction to the object.
Patent Document 1: JP-2005-55226A corresponding to US-2005/0024625A
According to the technique disclosed in the Patent Document 1, however, rotational position of the light reception mirror is detected by a resolver or a rotary encoder, which brings a difficulty associated with an increase in size of the range sensor. Further, the technique proposed in Patent Document 1 employs a relatively large scale configuration where a hollow structure motor drives the rotation axis, which is integrated with a cover of the light reception mirror etc. Thus, there arises a difficulty associated with an increase in size of the resolver and the rotary encoder, and inhibition of the range sensor from having a smaller size and lighter weight as a whole.